The area, weight and 4 linear variables were measured in each aortic valve cusp in 100 necropsy patients with normally functioning aortic valves, and the voluem of each sinus of Valsalva and the aortic area at the sinotubular junction were determined in the same patients. The sums of the aortic valve cuspal areas, cuspal weight and sinus of Valsalva volumes increased with age (p less than 0.001) and with heart weight (p less than 0.001). All 3 variables (cuspal area, cuspal weight and sinus of Valsalva volume) also increased with age and heart weight relative to each other. The luminal area of aorta at the sinotubular junction also inccreased with age and heart weight and it also increased as the sum of the aortic valve cuspal areas and weights and sinus of Valsalva volumes increase. In only 16% of the 100 patients were the 3 aortic valve cusps of similar size (less than 5% difference in area between cusps); in 51%, 1 cusp was of different size than the other 2, and in 33% of patients all 3 cusps were of different sizes.